Apparatus for parallel detection of the behaviour of mechanical micro-oscillators

Abstract

The invention concerns an apparatus for parallel detection of the behaviour of mechanical micro-oscillators interacting with the sample ( 21 ). The amplitude and the phase of resonance of micro-oscillators ( 12 ) are measured with optical means. The invention is characterised in that a source ( 1 ) is active during a fraction 1/n of the period (n being an integer) and of variable phase p/n of the period (p being an integer). Interferences are produced between light beams generated by reflection of incident light beams ( 7 ) and ( 8 ) on the micro-oscillators ( 12 ). Periodically the micro-oscillators ( 12 ) are displaced by means. The value of the parameter p (p being an integer) is varied and N elementary measurements are integrated to obtain a measurement representing each of the values of p. The phase and amplitude of each micro-oscillator ( 12 ) are calculated on the basis of the representative data obtained for each value of p and this for a large number of accumulations. The invention is applicable in the field of nanotechnologies.

1. An apparatus for parallel detection of the behaviour of mechanical micro-oscillators, comprising:
 a support ( 15 ); 
 a multichannel detector ( 14 ) 
 a plural number of mechanical micro-oscillators ( 12 ) mounted on the support ( 15 ) and positioned for interacting with a sample ( 21 ), each micro-oscillator having a micro-oscillator end ( 10 ,  11 ) and an output; and 
 an optical means for measuring an amplitude and a phase of oscillations produced by the micro-oscillators ( 12 ), said optical means comprising 
 i) a periodic luminous source ( 1 ) for generating an incident luminous beam ( 4 ), the luminous source active during a fraction 1/n of a period (n integer) and with a variable phase (p/n) of the period (p integer), 
 ii) operatively connected to an output of the luminous source, to receive the incident luminous beam ( 4 ) from the luminous source, a means for splitting and polarizing the incident luminous beam comprising 
 a) a means for producing, from the incident luminous beam ( 4 ), a reflected and modulated luminous beam, and 
 b) a means for splitting said reflected and modulated luminous beams into separate polarized beams ( 7 ,  8 ) directed to each of the micro-oscillator ends ( 10 ,  11 ), and 
 iii) an interference means operatively connected to a) the means for producing reflected and modulated luminous beams and b) the outputs of the micro-oscillators ( 12 ), the interference means producing an interference image of the reflected and modulated luminous beams based on the outputs of the micro-oscillators ( 12 ), the interference image being directed to the multichannel detector; and 
 the multichannel detector ( 14 ) comprising 
 i) plural channels equal in number to at least the plural number of micro-oscillators, 
 ii) a means for periodical displacement of the micro-oscillators ( 12 ) as a group ( 21 ), 
 iii) a means to vary the value of the period of the luminous source and to integrate plural elementary measures to obtain a representative measurement for each value of the period, and 
 iv) a computer ( 20 ) enabled to record, in a buffer memory, representative data obtained for each value of the period for a number of accumulations and then enabled to calculate the phase and the amplitude of each micro-oscillator ( 12 ). 
 
     
     
       2. An apparatus according to  claim 1 , wherein,
 the means for periodical displacement of the micro-oscillators comprises piezoelectric ceramics ( 16 ) with an electrical excitation frequency ( 18 ) synchronized with the luminous source ( 1 ). 
 
     
     
       3. An apparatus according to  claim 2 , wherein,
 the support ( 15 ) is a silicon plate, mounted directly on the piezoelectric ceramics ( 16 ). 
 
     
     
       4. An apparatus according to  claim 1 , wherein, a free end ( 11 ) of the micro-oscillators ( 12 ) is functionalized for selective and differentiated detection of the sample ( 21 ). 
     
     
       5. An apparatus according to  claim 1 , wherein,
 the means for producing reflected and modulated luminous beams comprises a polarization cube separator ( 5 ) for linear polarization of the incident luminous beam, and 
 the means for splitting said reflected and modulated luminous beam into separate polarized beams ( 7 ,  8 ) directed to each of the micro-oscillator ends ( 10 ,  11 ) comprises a Wollaston prism ( 6 ) for splitting the reflected and modulated luminous beam into two orthogonally polarized beams ( 7 ,  8 ). 
 
     
     
       6. An apparatus according to  claim 2 , wherein,
 an assembly composed of the micro-oscillators ( 12 ), of the support ( 15 ) and of the piezoelectric ceramics ( 16 ) is placed on a bench, the assembly being at atmospheric pressure. 
 
     
     
       7. An apparatus according to  claim 1 , wherein,
 a means to vary the value of the period of the luminous source comprises a sequencer ( 2 ) operatively connected to synchronize detection ( 17 ) of the interference image, operation of the luminous source ( 1 ) and operation of the piezoelectric ceramics ( 16 )). 
 
     
     
       8. An apparatus according to  claim 1 , wherein,
 the multichannel detector comprises a zoom ( 13 ) and a digital CCD camera ( 14 ). 
 
     
     
       9. An apparatus according to  claim 1 , wherein,
 the multichannel detector comprises a microscope and an analogic camera. 
 
     
     
       10. An apparatus according to  claim 3 , wherein,
 an assembly composed of the micro-oscillators ( 12 ), of the support ( 15 ) and of the piezoelectric ceramics ( 16 ) is placed on a bench, the assembly being at atmospheric pressure. 
 
     
     
       11. An apparatus for parallel detection of the behaviour of mechanical micro-oscillators, comprising:
 plural micro-oscillators ( 12 ) with outputs; 
 a multi-channel detector; 
 a luminous source ( 1 ); 
 a sequencer ( 2 ) controlling the luminous source so that the luminous source emits a periodical incident beam ( 4 ) represented by a function ( 3 ) taking a first value during a fraction (1/n) of a period and another value outside the fraction of the period; 
 connected to receive the incident beam, a means for splitting and polarizing the incident beam comprised of a polarization separator ( 5 ) and of a prism ( 6 ), the polarization separator producing a linearly polarized luminous beam directed toward the prism, the prism separating the polarized luminous beam into orthogonally polarized beams ( 7 ,  8 ) directed respectively toward each of the micro-oscillators; and 
 an interference means operatively connected to the separator and to the outputs of the micro-oscillators and comprised of a lens ( 13 ), with an interference based on the output of the micro-oscillators, the lens focusing reflected beams of the separator on the multichannel detector, 
 the multichannel detector ( 14 ) comprising 
 i) plural channels equal in number to at least the plural micro-oscillators, 
 ii) a means for periodical displacement of the micro-oscillators ( 12 ) as a group ( 21 ), 
 iii) a means to vary the value of the period of the luminous source and to integrate plural elementary measures to obtain a representative measurement for each value of the period, and 
 iv) a computer ( 20 ) enabled to record representative data obtained for each value of the period for a number of accumulations and then enabled to calculate the phase and the amplitude of each micro-oscillator ( 12 ). 
 
     
     
       12. The apparatus of  claim 11 , wherein,
 the detector further comprises a CCD camera ( 14 ). 
 
     
     
       13. The apparatus of  claim 11 , wherein,
 the micro-oscillators have a calculated resonance frequency of 120.19 KHz. 
 
     
     
       14. The apparatus of  claim 11 , wherein,
 the micro-oscillators are comprised of piezoelectric ceramics ( 16 ) to move the micro-oscillators as a group. 
 
     
     
       15. The apparatus of  claim 14 , wherein,
 the sequencer controls acquisition of the interference images, synchronization of the piezoelectric ceramics and triggering of the luminous source. 
 
     
     
       16. The apparatus of  claim 15 , wherein,
 the sequencer controls the luminous source to be active for a quarter of the period with a varying phase value. 
 
     
     
       17. An apparatus for parallel detection of the behaviour of mechanical micro-oscillators, comprising:
 plural mechanical micro-oscillators ( 12 ) with outputs; 
 a multi-channel detector; 
 a luminous source ( 1 ); 
 a sequencer ( 2 ) controlling the luminous source so that the luminous source emits a periodical incident beam ( 4 ) active during a fraction of a varying period; 
 a polarization separator ( 5 ); 
 a prism ( 6 ), 
 the polarization separator ( 5 ) connected to receive the incident beam from the luminous source and reflect the beam producing a linearly polarized luminous beam directed toward the prism, 
 the prism separating the polarized luminous beam into orthogonally polarized beams ( 7 ,  8 ) directed respectively toward each of the micro-oscillators; and 
 an interference means operatively connected to the separator and to the outputs of the micro-oscillators and comprised of a lens ( 13 ), with an interference based on the output of the micro-oscillators, the lens focusing reflected beams of the separator on the multichannel detector to produce interference images, 
 the multichannel detector ( 14 ) comprising 
 i) plural channels equal in number to at least the plural micro-oscillators, 
 ii) a means for periodical displacement of the micro-oscillators ( 12 ) as a group ( 21 ), 
 iii) a means to vary the value of the period of the luminous source and to integrate plural elementary measures to obtain a representative measurement for each value of the period, and 
 iv) a computer ( 20 ) enabled to record representative data obtained for each value of the period for a number of accumulations and then enabled to calculate the phase and the amplitude of each micro-oscillator ( 12 ). 
 
     
     
       18. The apparatus of  claim 17 , wherein,
 the sequencer controls acquisition of the interference images, synchronization of movement of the micro-oscillators, and triggering of the luminous source. 
 
     
     
       19. The apparatus of  claim 18 , wherein,
 the sequencer controls the luminous source to be active for a quarter of the period with a varying phase value.